Oil well pump



W. S. CRAKE OIL WELL PUMP May 8, 1951 Filed Jan. l1, 1949 Fm. /a

Patented May 8, 1951 OIL WELL PUMP Wilfred S. Crake, Houston, Tex., assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware Application January 11, 1949, serial N0.17o,324

Claims.

This invention relates to the art of producing hydrocarbon materials from underground formations,` and pertains more particularly to an improved oil well pump adapted to be actuated by the reciprocation of the tubing string.

Conventional oil well pumps are usually operated by reciprocating a string of sucker rods Within a tubing or flow string which is, in turn, run within the well casing. The pump is installed at the lower end of the tubing string and is sup-- ported thereby, the pump plunger being reciprocated through said sucker rod string by suitable prime-mover means at the surface. The sucker rod string is furthermore used, in well known fashion, to install and to withdraw the plunger and travelling valves of the pump.

A modification of this system is to be found in so-called easing pumps, wherein the pump is anchored directly in the well casing at the desired depth, and the tubing string is eliminated, the sucker rods reciprocating directly within the casing. The casing pump depends for its operativeness on the feature of packing off the casing above the pump, whereby the casing itself serves as a, tubing string. This type of pump is, however, not suitable for Wells having low fluid levels and producing large or even normal quantities of formation gas, because'the gas can be produced to the surface only through the pump, and causes frequent failures of the pump due to gas lock.

In my previous Patent No. 2,383,934 on an Oil Well Pump, there is disclosed an oil well pump of the reciprocating-plunger type adapted to be reciprocated by a tubing string, said pump comprising a valved plunger affixed to the lower end of said tubing string, a pump barrel slidingly fitting around said plunger, and upper and lower anchoring means outwardly carried by the pump barrel to anchor the pump barrel against upward and downward motion, respectively, in the Well. The upper anchoring means is adapted to be set in the well in response to an axial movement of the tubing string with respect to the pump barrel after the pump barrel has been anchored in the well by the lower anchoring means.

While the aforesaid apparatus is extremely useful, it has been found that during operation of said pump the lower anchoring means or holddown mechanism was often subject to accidental tripping, thus necessitating the reanchoring of the pump within the well.

Additionally, the above-mentioned method of anchoring pumps in a well necessitates the manipulation of the entire tubing string, either axially or rotationally, in order to actuate the anchoring means carried by said pumps.

It is, therefore, an object of the present invention to provide a pump system wherein the tubing string is used during operation, as actuating means for supplying motive power to the pump, as conduit means for conveying the liquid output of the pump to the surface, and as conduit means for supplying an actuating fluid for the hydraulically-operated anchoring means carried by said pump.

It is also an object of this invention to provide an improved and simplified pump installation wherein the sucker rod is eliminated and the pump, carrying hydraulically-operated anchoring means, is installed, reciprocated during operation, and removed solely by means of the tubing string.

Another object of the present invention is to provide a pump, adapted to be actuated 4by a tubing string, including a single hydraulically-operated anchoring device carried by said pump for xedly anchoring said pump in a well against both upward and downward motion.

These and other objects of this invention will be understood from the following description taken with reference to the attached drawing wherein:

Figures 1 and 1a are longitudinal views, partly in cross section, showing the present pump anchored in place within a well casing.

Figure 2 is a cross-sectional view of the lower end of the pump plunger shown in Figure la, said View being taken at thereto.

Figure 3 is a cross-sectional View of the tubing drain of Figure 1 in an open position.

Referring to Figure 1 of the drawing, the present pump is shown as being positioned in a well having a casing Il and a casinghead 9, provided with suitable conduit connections 8 for the removal of gases entering the casing in the well. The pump is attached to the end of a tubing string 5 which passes into the casing through a suitable lubricator device l. The tubing 5 serves for imparting a reciprocating motion to the pump, as will be described hereinbelow, and is for this purpose connected at 3 to a cable or similar means 2 leading to prime mover means such as a walking beam, not shown. The tubing 5 also serves as a ow or eduction tube for oil being pumped, and is connected, through a swivel head l, to an output conduit l.

Secured to the bottom of the tubing string 5 by a coupling I2 is a tubing drain I3 of a suitable type. In this embodiment the tubing drain I3, shown in Figures 1 and 3, may comprise two short 3 concentric tubular members I4 and I5 respectively. The inner tubular member I4 is mounted for limited axial and rotational motion within the outer tubular member I5, said axial movement being limited by an annular inner` ange I6 formed on the inner surface of the outer member I and an annular outer-ilange I1 carried by theV inner member I4.

The outer member I5 has formed therein a J -slot I8 adapted to receive a pin I9 carried onfV the outer surface of the inner member I4. One

or more iluid outlet ports 2U formed in the wallsof said outer member I5 permit fluid'to drain out of the tubing string 5 when the drain I3 vis in its` open position, as shown in Figure 3. When the pin I9 engages the slot I8, aslshown in Figure 1, the tubing drain is in its closed posti'on`with the annular flange I1 closing the fluid outlet ports and the tapered lower surface 2I of said angebeing seated on a shoulder 22 formed within said outer tubular member I5. The lower end 23 of the inner tubularmember I4 extends below the flange I1 and carries a sealing'ring 24, of any suitable packing material, which forms a fluidtight seal with the inner Wall of the outer tubular member I5Awhen the tubing drain is closed or in the pumping position. During pumping operations, fluid passes upward through coaxial bores 25 and 26 of the tubing drain I3.

Secured by screw threads 21 to the outer and lower tubular member I5 of the tubing drain I3 andin communication with the bore 25 thereof is a section of tubing 23 forming the upper polished plunger that extends through thel upper barrel 29 into the enlarged lower pump barrel 30 to form an annular chamber 3l between said tubing 28 and barrel 29 and a second annular chamber 32 between said tubing 28 and barrel 30. Attached to the lower end of thetubing 28, as shown at 53 is a hollow plunger 51, having an outside diameter larger than that of the tubing 28and adapted for a sliding t withiny the barrel 3D. The plunger 51 is provided with a passage or fluid port 65, opening to the space within the lower pump barrel below the plunger and forming a valve seat for an upwardly opening ball valve 6I, held in place by a baille plate 59. The plunger also has ports 55 in communication with. the space within the pump barrel'above the plunger.

The tubing 28 is provided, at a suitable distance above the plunger, with lateral portsll in communication with-the chamber 32. Mounted .within the tubing 28 above these ports is a valve structure comprising a valve seat 40, an upwardly opening ball valve 38, a baffle pin. 35, andv an orifice 42.

The lower pump barrel 3Q' is closed near thev lower end by a transverse member or plate 51, having therethrough an orifice or uid port 55 in register with a downwardly extending tube 59 depending from said plate. Portsv 1I are formed in the walls of the pump barrel abovev the lower end of the tube 5S to permit theinllow of uidY from the well, andthe pumpbarrel or' housing 35y is closed at its lower-endby al bull plug12, the arrangement 51`-55"-1I thusform` ing in -el'ect a gas anchor for the pump. A key 62,' integrally formed on or fiXedly secured to the bottom of the plunger'EI, is adapted to engagea keyway E3 in the plate S1.

Inthis embodiment the upper pump barrel `is divided into two sections 29 and 29A that carry between them' suitable' hydraulicallyeop'eratedl" pump and anchoring means for positioning said 4 pump in the well casing Il at any predetermined depth.

The pump anchoring means comprises a tubular mandrel 33 having internally threaded end portions 34 and 35 whereby it is connected to the upper pump barrel sections 29 and 29A thus formingv a portion of the upperbarrel. A series of ports'S'I extendllaterally through the-.mandrel 33 and provide piston chambers for pistons 39 that are; alTiXed to or integrally formed with a plurality of slip segments 4I. The inner and outer surfaces of the slips 4I are curved so that said innersurfaces conform to the outer surface of the mandrel 33, and said outer surfaces con- -form substantially to the inner surface of the casing II. The outer surfaces 45 of the slips 4I are 'serrate'd or toothed, preferably in a V-shape to prevent slippage of the pump in either direction. The slips 4I are mounted for limited lateralor radial movement and are actuated by fluid Apressure'acting "against'th'el pistons 39. The pistons' 35 m'ay be equipped with suitable' pis'- tonV rings o'r O-riri'g"seals43z to' forma fiuidtight'" seal between'said'pistons 4I and thewallof the" piston chambers. The' annular chamber' 3l formed between thetubing member' 28" and the mandrelV 33 is in communication with theinside' of said tubingm'ember 28 through portmearis or apertures 41 in the wall of said tubing member 28f The upper barrel 29"'and 29A' isiswagedlatits' upper and'lower ends'l3and'14; respectively, inv substantially iiuidtight contact Witlrthe 'tubing member 22: Preferably, however; one-ormore seal cupsA 15 andllare` carried on the'tubin'g member 28- on either' sideA of the'apertures ,41:

therethrough thus-forming' a= pressurecchamber' 3| between said tubingI member 28,'n mandrel 33 and seal cups 15*an`cl"16." If desired", a central` izing spring 11 may besecuredtothe upperbar' relV 29 in anysuitable'manner Lto position'the'bare Additionally a v rel centrally` in the-- casing II;` rubber casing protector 'I8l maybefa'flixed to the tubing string 5i to prevent"thetubing drain' I3 from" contacting' the`- casi-ng'. I i while' the pump is beingreciprocated.'

In operations, the'I abcve-desciibed apparatus` isY lowered on the'end' of a'l tubing st'ring'5"to"a` predetermined level a well; With the pump' at'the 'desired 'depth thetubingstring '5"is filled;`

TheV fluid added to thensectionv of tubing 28-Y ows out the tubingd apertureslll iilling. chamber 3| between. saidl tubing 23-andmandrel 33; Thus, any fluid inA said tubingfrandl 28- becomes the pressure fluid for actuating thepistons 33 When aV engage the walls of the casing. I'I, as shownin` Figure-1.

The pump is now installed'and anchored within the casing II against either dwnward' or upward motion and is ready for reciprocaticn oi the tubingv.' Dringpumping, th'elengthsy of thel stroke oftheplunger, 5A1vand tubinguZiivare selected so that the plunger 51 and the tubing The tubing drainl I3`is, .01'."cou1'se, in a.

drain I3 do not strike the plate B1 and upper barrel 29 at the end of the down stroke, and plunger 51 does not.strike the top of the lower pump barrel 30 at the end of the upstroke of the pump. Also, the seal cups 15 and 16 are spaced so that they do not strike the swaged ends 13 and 14 of the upper pump barrel 29 and 29A.

' As the pump plunger 51 is reciprocated within the pump barrel 30 by meansof tubing string 5 and suspending elements 2 and 3 from a prime mover` element on the vsurface such as a walking beam, not shown, the now of well liquid proceeds to the surface as follows:

During the downward stroke, valve 38 is closed by the column of fluid in the tubing 5 and the well fluid enters the lower pump barrel 38 through ports 1I and 69, passes into the plunger 51 as valve 6I is open and thence into chamber 32 through ports 55 due to the vacuum created in chamber 32 above the plunger 51 by the downward displacement of said plunger. On the upward stroke, the valve 6I is closed and the fluid displaced from the chamber 32 by the rising plunger is forced through ports 44, past opened valve 38, upwards through the tubing 28, tubing drain I3 and into tubing string 5. Throughout the pumping operation the pressure fluid in the tubing 5 is preferably in communication with the pressure chamber 3l through apertures 41.

The tubing 28 and plunger 51 are normally of suflicient length so that an additional lowering of the plunger 51 below the lowest point in its normal downstroke permits it to contact the plate 61. When it is desired to raise the pump out of the well the tubing string 5 and tubing 28 are lowered until the plunger touches the plate 61. The tubing 5 is then rotated slightly from the surface until the key 52 on the bottom of the plunger 51 engages the keyway 63 in plate 61. Thus, plunger 51, tubing 28 and the outer tubular member I5 fixedly attached to said tubing 28 are restricted from further rotary motion. Continued rotation of the tubing string 5 in a clockwise direction causes the pin I9 to move out of the J -slot of the tubing drain I3, whereby the tubing string 5 and inner tubular member I4 attached to said tubing string may be raised. As shown in Figure 3, on raising the inner tubular member I4 of the tubing drain the flange I1 normally closing the drain ports 20 is raised opening said ports 20 thus permitting the liuid to drain from the tubing string 5 out the ports 20 and into the well again. With the pressure fluid drained from the tubing 5, pressure is removed from the pressure chamber 3I of the pump anchoring means allowing the slip segments 4I to be forced back against the mandrel 33 by contact with the casing II when the pump is removed from the well.

The construction of the tubing pump of the present invention has been found to be particularly advantageous in that only a single hydraulically operated anchoring means need be employed to securely anchor the pump in the well casing against either upward or downward movement. The pump also may be set and securely anchored without manipulation of the tubing string.

I claim as my invention:

1. A well pump Vadapted to be positioned within the casing of a well at the end of a reciprocating string of tubing, said pump comprising a valved plunger aixed to the lower end of said tubing for reciprocation therewith, a pump barrel slidably surrounding said plunger and the lower portion of. said tubing, and hydraulically 6 5 operated slip means outwardly mounted'on said barrel, said slip means comprising piston means responsive to the hydraulic pressure of a fluid standing in the tubing for engaging said slip means with said casing to anchor said pump therein.

2. A pump installation for well producing a fluid through a string of casing, comprising a string of tubing within said string of casing, prime mover means aiXed to the upper end of said string of tubing for reciprocating said string of tubing, a valved plunger -afxed to the lower end of said string of tubing for reciprocation therewith, a pump barrel slidably surrounding said plunger and the lower portion of said tubing, and hydraulically operated slip means outwardly mounted on said barrel, said slip means comprising piston means responsive to the hydraulic pressure of a fluid standing in the tubing for engaging said slip means with said casing to anchor said pump therein.

3. A well pump adapted to be positioned within the 4casing of a well at the end of a reciprocating ystring of tubing, said pump comprising a valved plunger aiixed to the lower end of said tubing for reciprocation therewith, a pump barrel slidably surrounding said plunger and the lower portion of said tubing, hydraulically operated slip means outwardly mounted on said barrel, said slip means comprising piston means affixed to said slip means responsive to the hydraulic pressure of a uid standing in the tubing for engaging said slipr means with said casing to anchor said pump therein, and a normally closed tubular drain element connected into the tubing string above said pump surface to drain said tubing of fluid, whereby said slip means are released from engagement with the casing.

4. A well pump adapted to be positioned within the casing of a well at the end of a reciprocating string of tubing, said pump comprising, in combination, a valved plunger affixed to the lower end of said tubing for limited stroke reciprocation therewith, a pump barrel slidably surrounding said plunger, said pump barrel having an upper and a lower luidtight section, said plunger being enclosed within said lower fluidtight section, hydraulically operated slip means outwardly mounted on said upper pump barrel section for limited lateral movement, said slip meansY comprising piston means aiixed to said slip means and carried by said upper pump barrel section, .port means through the wall of said tubing in .communication between the inside of said tubing and the space adjacent the piston means, said piston means being responsive to the hydraulic pressure of a fluid standing in the tubing for engaging said slip means with said casing to anchor said pump therein, a normally closed drain element connected into the tubing string above said pump, and locking means carried by said drain element and operable by manipulation of the tubing string from the surface to open said drain element, whereby said slip means are released from engagement with the casing by the draining of the fluid in the tubing.

5. A well pump adapted to be positioned within the casing of a well at the end of a reciprocating string of tubing, said pump comprising, in combination, a valved plunger aixed to the lower end of said tubing for limited stroke reciprocation therewith, a pump barrel slidably surrounding said plunger, said pump barrel having an upper and a lower fluidtight section, said plunger .being enclosed within said lower uidtight section, slip zassaizss means .outwardly mounted on :said npperpump barrel section for limitedf laterali'movement, aperturemeansthroughthe wall of 'said vtu-bingin communication :between the inside. ofv said tubing and the spaceinside .thekupper section-of said pump barrel, ports through the Wall of -said upperpump barrel `isectionin :register with the inner faces of said slip means, `piston vmeansfafxed to vsaid slip means mounted xfor lateral movement in. sai'd port means,Y said pistonmeans beingresponsive to thevhydrraulic pressurecfa fluid @standing inthe tubing for engaging gsaid slip means withvsaid casing 11o-*anchor saidA pump therein, and a normally closed tubular draineement connected into the tubing' string-:above said 15 523333,934

pump' andoperame from' the surface toidrain said tubingfofffiui'd whereby sai'dslip means arexreleased fromngagement with the casing.

WILFRED S. .CRAKE.

REFERENCES CITED The following V'reierences are of record'inthe le ofthis patent: 

